旗草内生真菌的遗传多样性分析

Genetic Diversity of Endophytic Fungi Acremonium implicatum in Brachiaria

从形态学水平和DNA水平上对11个旗草内生真菌交织顶孢霉Acremonium implicatum分离物的遗传多样性进行研究。结果表明,分离物在形态学和DNA水平上都表现出遗传多样性。在PDA培养基上,依据生长特性将这11个分离物划分为9类。通过11个随机引物对旗草内生真菌分离物基因组DNA进行RAPD分析,当相似系数为0.93时,11个旗草内生真菌分离物被聚类为7组。用4对选择性引物进行AFLP分析,当相似系数为0.95时,这些分离物也被聚类为7组。RAPD聚类结果与AFLP聚类结果的相关系数大于0.98。RAPD和AFLP聚类结果与形态学上的分类基本一致。旗草内生真菌分离物遗传多样性的存在,说明在A.implicatum的自然株系中有可能筛选出有利于旗草生长,但却不产生家畜毒性物质的优良菌株,从而加速旗草的抗性育种和高产育种。

Diversity of 11 isolates from endophytic fungi Acremonium implicatum in Brachiaria spp. was studied based on their cultural characters, RAPD and AFLP. These isolates showed diversity both in the cultural characters and DNA markers. According to the cultural characters on PDA medium, the 11 isolates were probably clustered into 9 groups, while they were clearly clustered into 7 groups at similarity coefficients of 0.23-0.93 based on RAPD with 11 arbitrary 10-bp primers or at similarity coefficients of 0.26- 0.95 based on AFLP with 4 selective primer combinations. Results of AFLP analysis are consistent with those of RAPD at a relative coefficient of 0.98. In general, the clustered groups were consistent both in cultural characters and DNA markers based on the RAPD and AFLP. Because of the existence of genetic diversity, natural strains of A. implicatum that are conducive to plant growth and toxin-free to livestock might be selected for Brachiaria breeding.